1. Field of the Invention
The present invention relates to in-vehicle imaging and sensing and, more particularly, to a device that determines whether a vehicle passenger seat is unoccupied, is occupied by a person, or is occupied by a child seated in a rear-facing child carrier.
2. Description of Related Art
As the needs and desires for automobile safety enhancement features increase, injuries attributable to such safety equipment and devices themselves are exacerbated. For example, automobile passenger-side inflatable restraints (airbags) in automobiles equipped with such supplemental safety devices are generally deployed upon a sufficiently severe impact of the front section of the vehicle. However, it has been found that rear-facing child carriers, i.e., where the restrained child faces the passenger seat back of the automobile, may be potentially hazardous, and possibly perilous, upon deployment of an airbag. Serious damage to the child restrained in a typical child carrier could occur when the airbag first deploys, shooting out at speeds up to 200 mph. As illustrated in FIG. 1, the inflating airbag 110 deploys over the top of the child seat 112 and transfers a force to the back of the seated child's head.
In addition to possible injury of the child due to the direct contact with the airbag, injuries could also occur to a child in a rear-facing child carrier if a deploying air bag pushes the child restraint 112 into the passenger seat back 114. Although it will be recognized that a safer mode of travel for a child in a child carrier is in the back seat of a vehicle, some vehicles do not have back seats (e.g., trucks and small sports cars), while in other vehicles the back seat may be unable to accommodate a child carrier.
Furthermore, in some vehicles which have small cab areas, such as compact pick-up trucks and sports cars, deploying may cause damage to the vehicle as well as injury to the driver if the vehicle windows are closed during an impact. In such instances, if both driver and passenger airbags deploy during impact, the side windows of the vehicle could be shattered and the eardrums of the driver ruptured due to the rapid air pressure increase in the small interior volume. Moreover, the replacement cost of a passenger airbag after deployment, which would otherwise not have been necessary due to the absence of such a passenger, may be substantial.
Thus, to increase child safety in a rear-facing child carrier, as well as to lower the cost of unnecessarily deployed airbags, a variety of detection technologies have been suggested. For example, manual override switches may be installed to allow a driver to disable the passenger-side airbag manually. Such devices, however, become ineffective in instances where the driver or operator simply forgets to turn the switch on or off depending upon the existence of a passenger or a child in a rear-facing child carrier in the automobile passenger seat. Even such enhancements as dashboard indicators or automatic reset arrangements would not be foolproof. If a driver transporting a child in a rear-facing child carrier makes frequent stops, the requirement that the driver continually manually reset the switch could be cumbersome.
Other safety-enhancement schemes for occupant detection include radar or ultrasonic technologies. Sensory devices which detect radar or sound waves may be installed in the dashboard or in the passenger seat itself. However, if the dashboard is blocked or the seat is covered, accurate detection of a passenger in the passenger seat would be hindered. Moreover, it has been found that consumers generally do not like the idea of "beams and waves" being directed at them. Consequently, such approaches are typically not preferred.